In general, a refrigerator supplies cool air generated using a refrigeration cycle to storage chambers and stores articles in a low temperature state in the storage chambers.
The storage chambers provided in the refrigerator include a refrigerating chamber to store food in a low temperature state and a freezing chamber to store food in a frozen state.
The refrigerator includes a cabinet including the storage chambers, doors provided on the cabinet to open and close the storage chambers, and a cooling system to supply cool air to the storage chambers using the refrigeration cycle.
The cabinet includes an inner case having a space to form the storage chambers and an outer case surrounding the inner case, a foamed heat insulating material for heat insulation fills a space between the outer case and the inner case, and the cooling system including a compressor, a heat exchanger and the like is provided at the lower part of the cabinet.
The outer case is formed of a metal and the inner case is formed of a resin having excellent impact resistance and heat resistance. In this case, an acrylonitrile butadiene styrene (ABS) copolymer may be used as the resin.
The door also includes an inner case and an outer case, a foamed heat insulating material fills a space between the inner case and the outer case, the outer case is formed of a metal, and the inner case is formed of a resin.
The outer cases of the cabinet and the doors are manufactured by pressing and punching a metal sheet.
The inner cases of the cabinet and the doors are manufactured using a vacuum molding method.
In case of the vacuum molding method, a resin sheet for molding is heated so as to be easily deformed and then located at a vacuum case, one side of which is opened, and the inside of the vacuum case is evacuated so that a part of the heated sheet is introduced into the vacuum case. Here, since the edge of the resin sheet is fixed to the outside of the vacuum case, the middle part of the resin sheet swells and is sucked into the vacuum case and, thus, the resin sheet is firstly molded.
Thereafter, a mold having a shape corresponding to a desired inner case is located close to the firstly-molded resin sheet, air of a high pressure is supplied to the inside of the vacuum case so that the resin sheet is closely attached to the mold and, thus, the firstly-molded resin sheet is secondarily molded.
Thereafter, the resin sheet closely attached to the mold is cooled and then, an acquired molded inner case product is released from the mold, unnecessary parts are removed from the acquired molded the inner case product, and grooves and the like required for assembly are formed on the molded inner case product.
In such a vacuum molding method of the inner case, if the height of a storage chamber is less than the depth of the storage chamber, when the resin sheet heated during vacuum molding swells and is sucked into the vacuum case, the resin sheet may tear. The reason for this is that, if the depth of the storage chamber is increased, the storage chamber having a large volume needs to be molded using the resin sheet having a designated area and thus the resin sheet swells, decreases in thickness, and then tears.
Due to such a problem, if the depth of the storage chamber is great, after a barrier to divide the storage chamber is separately manufactured and the inside of the barrier is filled with a foamed heat insulating material, such as Styrofoam, the barrier is installed within the inner case. Otherwise, after a space between the inner case and the outer case of the cabinet is filled with a foamed heat insulating material, a space between the inner case and the outer case of the barrier is filled with a foamed heat insulating material, i.e., a foaming process is carried out twice.
However, in the former method in which the barrier filled with a foamed heat insulating material is separately manufactured and installed in the inner case, a gap is generated between storage chambers and, thus, the storage chambers are not completely divided from each other, and a new process for filling the inside of the barrier is required and thus material costs and investment costs are generated.
Further, in the latter method in which the inside of the barrier is filled with a foamed heat insulating material after filling of a space between the inner case and the outer case with a foamed heat insulating material, urethane foam may be deformed and a foaming liquid may leak through a gap of a sealing surface between the inner case and the barrier.